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Old 12-23-2008, 08:57 AM
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supercharged SBC tuning:

First off Merry X -mas gang!
The car is a '71 chevy caprice(4200+ lbs) and the spec sheet reads as follows:
- 350" "hencho en mexico" servicemaster sbc- fine cast china internals(but FRESH!) 8.5:1 cr
- dart 200cc pro 1 alums. -unported
- Magnuson 122" high helix supercharger-7 lbs.
- 770 cfm holley street avenger prepped by The carb shop
- Snow performance methanol injection- to combat possible detonation
-TH-400 w/ TCI 2500 stall, 10 bolt w/3.42's and fresh posi

I will assemble a healthier short block soon , so this engine is more of a testbed to acclimate myself with a blown engine(this is my first).I am also curious just what this engine will take, so I have aptly named it "THE ALAMO". While trying to be adventerous with seeking power, im also attempting to ensure I have safety devices in use to keep from grenading this engine while learning,and make safe horsepower, as to not destroy the expensive hardparts. Please keep this in mind when making your recommendations.Aside from the top end and electronics, nothing from this engine will go on to the next. The next shortblock will be large, forged , and roller, and boost will be increased heavily. my plan is to change shortblocks, change pulleys, retune(new carb most likely), and blast off


I neglected to list any other hard parts because i need help picking them. Going to have to run a flat tappet cam.. any suggestions? I was looking at the K-1105 kit from summit. Can I get any closer with an off the shelf grind?I heard a wide LSA is recommended with blowers, any other cams out there you can think of? will it be hard to fill the cylinders with those big heads and a small cam like that to see 7 lbs. of boost?

Ignition is my next main concern. I was planning to use Summit racings own brand ignition box with boost timing master, which retards timing according to boost level. Is this overkill in this application? Can i use my stock electronic converted distributor(with revised timing curve) or do i need something more fancy?I assume i can run the box in tandem with the methanol injection?I read alot of initial lead is liked by blowers, with low advance.when should i have all the timing in by? Ive read the magnuson makes power all the way down around 2k rpms..

Finally: lets say i build a 400+" SBC in hopes of 700+ horsepower, can the magnuson support it at 122"?

A little lost here, so some guidnace would be great. thanks in advance - Alex

P.S. - I was hoping for around 400 hp at the wheels with "the alamo", think it can be done?

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Last edited by WsXs3; 12-23-2008 at 09:10 AM.
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Old 12-23-2008, 03:05 PM
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Here are recommendations from Blower Drive Service. It's interesting to note that they recommend 110 LSA on gasoline and 112-114 on alcohol.
http://www.blowerdriveservice.com/recommend.php
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Old 12-23-2008, 03:40 PM
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The lil 122cid blower will not make 700hp or even close.
A Weiand 177 will make 600+hp on a 350 with high boost and race gas or Water injection and good pump gas. Should not require both boost spark retard with water/methanol injection at the same time. One or the other.
Use a better cam. You're going to be into the rpm that requires a solid flat tappet cam.
eg: crane F-280-2 or Crane F-290-2 With this cam+ high boost+ water injection you can simply lock out the spark advance (28 to 36deg)
850-950cfm competition carb.

Or 8-71 and two 750's

The lil 122 is going to top out around 450hp.

A weiand 177+ Nitrous oxide will make 700hp on a 350.
Twin 122CID huffers sucking thru two 750 carbs on a custom built blower manifold could make 700hp. Hell, just run it on Methanol.

Strong piston, rods and crank are required.
Exhaust headers sized to deal with 700hp worth of exhaust volume are required. 1-3/4 1-7/8 race headers.

Last edited by F-BIRD'88; 12-23-2008 at 04:27 PM.
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